The present invention relates to an image forming system comprising a plurality of image forming apparatus, such as digital copying machines, which are interconnected through a transmitting apparatus.
A digital copying machine, an example commercialized image forming apparatus, reads an original image by means of an image read section to process the read original image in a specified manner by means of an image processing section, and prints out the processed image data by means of a recording section as a copy image. Thus, the digital copying machine of this type produces an image on a sheet using only the image processing functions pre-installed therein.
On the other hand, an idea of forming a network by interconnecting a plurality of image recording apparatus or the like has been proposed recently. For example, Japanese Laid-Open Patent Application No. 116834/1978 (Tokukaisho 53-116834) discloses an arrangement to interconnect a plurality of image reading apparatuses and a plurality of image recording apparatuses through a single control section.
This arrangement enables each image recording apparatus to output a copy of an original image read by any of the above image reading apparatuses. Thus, when more than one kind of document is copied, each kind of document is set to a separate image reading apparatus and the copy is made by a single image recording apparatus, thereby reducing an idle time of the image recording apparatus compared with a case where each kind of document is set in a single image reading apparatus.
Also, Japanese Examined Patent Publication No. 36592/1995 (Tokukouhei 7-36592) discloses an image forming system including a plurality of copying machines interconnected through a single control apparatus, and each copying machine is furnished with an image read section and an image record section. In this system, image signals subject to recording are distributed to more than one copying machine according to a specified copying mode, so that those who received the image signals can carry out the copying operation in parallel.
However, the above conventional image forming systems has a number of problems.
To begin with, each image processing function of the digital copying machine depends on a software program, which has been developed at an increasing pace. Thus, the image processing function is upgraded in a short period and new models with additional functions have been steadily commercialized. Therefore, the state-of-the-art digital copying machine with desired image processing functions becomes an outdated model with relatively low level functions as soon as the user purchases it.
Because the user can neither upgrade the functions of his digital copying machine nor simply add new functions, if he wants higher level or new functions, he has to purchase a new model. This is an economic burden for the user and a manufacturers"" problem accompanying with their efforts in always meeting users"" demands.
The same can be said about a memory capacity of the digital copying machine. To be more specific, most of the higher level image processing functions, such as an electronic RDH (Recycle Document Handler) function, are feasible only when the digital copying machine has a large memory.
A possible solution to the above problem would be interconnecting copying machines through a transmitting apparatus to enable them to share their memories, a practical arrangement of which, however, has not been discussed in any of the prior art documents.
In addition, suppose that a first copying machine requests a second copying machine to store the transmitted data on its behalf, then, the second copying machine eventually accumulates a great volume of image data for a considerable period unless the first copying machine issues a return request of the image data. Thus, the memory of the second copying machine is occupied by the image data from the first copying machine. This limits the memory function of the second copying machine, in other words, this causes an insufficient memory at the second copying machine""s end, thereby hindering the full performance of the second copying machine.
It is therefore an object of the present invention to provide an image forming system, in which an image processing apparatus can share its memory with another image processing apparatus while reducing the capacitive burden of the shared memory.
The above object is fulfilled by an image forming system furnished with a first image forming apparatus, a second image forming apparatus, and a transmitting apparatus for connecting the first and second image forming apparatuses for mutual image data transmission,
wherein,
(1) the first image forming apparatus includes:
a recording section for forming a visible image based on image data;
a command input section for inputting an action command; and
a control section for transferring the image data from the first image forming apparatus to the second image forming apparatus through the transmitting apparatus at a command, inputted through the command input section, to issue a store request to the second image forming apparatus to store the image data on behalf of the first image forming apparatus, and
(2) the second image forming apparatus includes:
a storage section for storing image data;
a control section for storing the transferred image data from the first image forming apparatus into the storage section, and for returning the stored image data to the first image forming apparatus through the transmitting apparatus at a return request issued by the first image forming apparatus; and
an erasing section for erasing the stored image data in the storage section.
When the first image forming apparatus reads a document of plurality of pages using, for example, the electronic RDH (Recycle Document Handler) function, a data volume may exceed a capacity of the memory thereof in some cases.
However, the above arrangement can solve this problem. To be more specific, the operator inputs a command into the first image forming apparatus through the command input unit, directing the same to request the second image forming apparatus to store the image data on its behalf. Upon receipt of such a command, the control unit of the first image forming apparatus starts to transfer the image data to the second image forming apparatus through the transmitting apparatus. The image data can be transferred either partially or entirely.
Then, the second image forming apparatus stores the transferred image into its storage unit, and returns the stored image data to the first image forming apparatus upon receipt of the return request therefrom.
The first image forming apparatus processes the returned image data using specified functions and supplies the processed image data to the recording unit, which outputs the supplied image data in the form of a visible image.
According to the above arrangement, the first image forming apparatus can process the image data while using the storage unit of the second image forming apparatus.
If the first image forming apparatus has not issued the return request for a considerable period, the transferred image data are accumulated in the storage unit of the second image forming apparatus. Under these conditions, the memory of the second image forming apparatus eventually becomes insufficient, thereby causing some trouble in its operation.
To eliminate this problem, the erasing unit erases the image data in the storage unit as occasion demands.
Therefore, in the present image forming system, the first image forming apparatus can use the storage unit of the second image forming apparatus while eliminating operation troubles possibly causing at the second image forming apparatus""s end.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.